Anode for an organic electronic device

ABSTRACT

There is provided an anode for an organic electronic device. The anode is a conducting inorganic material having an oxidized surface layer. The surface layer is non-conductive and hole-transporting.

RELATED APPLICATION

This application claims priority under 35 U.S.C. §120 from U.S. Ser. No.12/467,567, filed on May 18, 2009 now U.S. Pat. No. 8,242,487, which inturn claims priority under 35 U.S.C. §119(e) from U.S. ProvisionalApplication No. 61/053,960 filed on May 16, 2008 which is incorporatedby reference in its entirety.

BACKGROUND INFORMATION

1. Field of the Disclosure

This disclosure relates in general to an anode for an electronic deviceand for the process for forming it.

2. Description of the Related Art

Electronic devices define a category of products that include an activelayer. Organic electronic devices have at least one organic activelayer. Such devices convert electrical energy into radiation such aslight emitting diodes, detect signals through electronic processes,convert radiation into electrical energy, such as photovoltaic cells, orinclude one or more organic semiconductor layers.

Organic light-emitting diodes (“OLEDs”) are an organic electronic devicecomprising an organic layer capable of electroluminescence. OLEDscontaining conducting polymers can have the following configuration:anode/EL material/cathodewith optionally additional layers between the electrodes.

A variety of deposition techniques can be used in forming layers used inOLEDs, including vapor deposition and liquid deposition. Liquiddeposition techniques include printing techniques such as ink-jetprinting and continuous nozzle printing.

As the devices become more complex and with greater resolution, there isa continuing need for improved materials and processes for thesedevices.

SUMMARY

There is provided an anode for an organic electronic device comprising aconducting inorganic material having an oxidized surface layer which isnon-conductive and hole-transporting.

There is further provided an organic electronic device comprising:

-   -   a substrate,    -   an anode comprising a conducting inorganic material having an        oxidized surface layer which is non-conductive and        hole-transporting    -   at least one organic active layer, and    -   a cathode.

There is further provided a process for forming an organic electronicdevice, comprising:

-   -   providing a TFT substrate having an inorganic surface layer;    -   forming a patterned anode on the TFT surface;    -   treating the anode with an oxygen plasma with a sufficient power        density and for a sufficient time to form a non-conductive,        hole-transport surface layer on the anode;    -   forming at least one organic active layer by a liquid deposition        technique;        -   applying a cathode.

The foregoing general description and the following detailed descriptionare exemplary and explanatory only and are not restrictive of theinvention, as defined in the appended claims.

BRIEF DESCRIPTION OF THE DRAWING

Embodiments are illustrated in the accompanying figure to improveunderstanding of concepts as presented in this disclosure.

FIG. 1 is one embodiment of an organic electronic device of thedisclosed invention.

DETAILED DESCRIPTION

Many aspects and embodiments have been described above and are merelyexemplary and not limiting. After reading this specification, skilledartisans appreciate that other aspects and embodiments are possiblewithout departing from the scope of the invention.

Other features and benefits of any one or more of the embodiments willbe apparent from the following detailed description, and from theclaims. The detailed description first addresses Definitions andClarification of Terms followed by the Anode, the Process, the OrganicElectronic Device, and finally Examples.

1. Definitions and Clarification of Terms

Before addressing details of embodiments described below, some terms aredefined or clarified.

The term “active material” refers to a material which electronicallyfacilitates the operation of the device. Examples of active materialsinclude, but are not limited to, materials which conduct, inject,transport, or block a charge, where the charge can be either an electronor a hole. Examples of inactive materials include, but are not limitedto, planarization materials, insulating materials, and environmentalbarrier materials.

The term “anode” is intended to mean an electrode that is particularlyefficient for injecting positive charge carriers. In some embodiments,the anode has a work function of greater than 4.7 eV.

The term “hole-transporting” refers to a layer, material, member, orstructure that facilitates migration of positive charge through thethickness of such layer, material, member, or structure with relativeefficiency and small loss of charge.

The term “layer” is used interchangeably with the term “film” and refersto a coating covering a desired area. The term is not limited by size.The area can be as large as an entire device or as small as a specificfunctional area such as the actual visual display, or as small as asingle sub-pixel. Layers and films can be formed by any conventionaldeposition technique, including vapor deposition, liquid deposition(continuous and discontinuous techniques), and thermal transfer.

The term “non-conductive,” when referring to a material, is intended tomean a material that allows no significant current to flow through thematerial. In one embodiment, a non-conductive material has a bulkresistivity of greater than approximately 10⁶ ohm-cm. In someembodiments, the bulk resistivity is great than approximately 10⁸ohm-cm.

The term “plasma” is intended to mean a collection of charged particlesthat respond strongly and collectively to electromagnetic fields, takingthe form of gas-like clouds or ion beams. Since the particles in plasmaare electrically charged (generally by being stripped of electrons), itis frequently described as an “ionized gas.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,method, article, or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive or and not to an exclusive or. For example,a condition A or B is satisfied by any one of the following: A is true(or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

Also, use of “a” or “an” are employed to describe elements andcomponents described herein. This is done merely for convenience and togive a general sense of the scope of the invention. This descriptionshould be read to include one or at least one and the singular alsoincludes the plural unless it is obvious that it is meant otherwise.

Group numbers corresponding to columns within the Periodic Table of theelements use the “New Notation” convention as seen in the CRC Handbookof Chemistry and Physics, 81^(st) Edition (2000-2001).

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of embodiments of the present invention, suitablemethods and materials are described below. All publications, patentapplications, patents, and other references mentioned herein areincorporated by reference in their entirety, unless a particular passageis cited in case of conflict, the present specification, includingdefinitions, will control. In addition, the materials, methods, andexamples are illustrative only and not intended to be limiting.

To the extent not described herein, many details regarding specificmaterials, processing acts, and circuits are conventional and may befound in textbooks and other sources within the organic light-emittingdiode display, photodetector, photovoltaic, and semiconductive memberarts.

2. Anode

One of the major issues facing OLED displays is the uniformity of theorganic layers within the pixel. In some embodiments, the pixel edge isbanked, using an organic photoresist or a ceramic material. The banksare present overlapping the edges of the transparent anode. This resultsin pixels that have increase in organic thickness going from the centerto the edge, and pixels with a lower aperture ratio due to a lower fillfactor. In some embodiments, the pixel edges are left uncovered, forexample, by spacing the bank some distance away. This results is adecreased layer thickness at the very edge. Furthermore, uncovered anodeedges would have severe current shunting. If current shunting could beprevented in the unbanked case, the display would benefit greatly fromboth a high fill factor as well as layer uniformity.

In addition, the surface of most conductive anode materials can havenonuniformities, including spikes of material. These can act as fieldconcentrators and be a source of leakage currents. In extreme cases,shorting defects may result. Thus, it would be beneficial if the spikescould be prevented from causing leakage current.

The new anode described herein comprises a conductive material, theexposed parts of which have been treated to form an oxidized layer whichis non-conductive and hole-transporting. Thus, the edges of the anodeare highly resistive and current shunting is prevented. In addition, thespikes are oxidized and no long act as undesirable conducting hot spots.

Any conventional transparent conducting material may be used for theanode so long as the surface can be plasma oxidized. As used herein, theterm “surface” as it applies to the anode, is intended to mean theexterior boundaries of the anode material which are exposed and notdirectly covered by the substrate. The anode layer may be formed in apatterned array of structures having plan view shapes, such as squares,rectangles, circles, triangles, ovals, and the like. Generally, theelectrodes may be formed using conventional processes, such as selectivedeposition using a stencil mask, or blanket deposition and aconventional lithographic technique to remove portions to form thepattern.

In some embodiments, the electrodes are transparent. In someembodiments, the electrodes comprise a transparent conductive materialsuch as indium-tin-oxide (ITO). Other transparent conductive materialsinclude, for example, indium-zinc-oxide (IZO),

Examples of suitable materials include, but are not limited to,indium-tin-oxide (“ITO”). indium-zinc-oxide (“IZO”), aluminum-tin-oxide(“ATO”), aluminum-zinc-oxide (“AZO”), and zirconium-tin-oxide (“ZTO”),zinc oxide, tin oxide, elemental metals, metal alloys, and combinationsthereof. The thickness of the electrode is generally in the range ofapproximately 50 to 150 nm.

The surface of the anode is plasma-oxidized, as discussed below.

3. Process

The new anode has an oxidized surface such that the edges and any spikesare highly resistive. This involves applying an intense oxygen richplasma oxidation step to the anode. This is not the same as theconventional low-power plasma or UVO cleaning step which normally takesplace. Such plasma cleaning steps have been disclosed as useful forremoving organic materials on contact pads, etc., in U.S. Pat. Nos.6,953,705 and 7,235,420. For the new anode described herein, the anodeis treated with an oxygen plasma with a sufficient power density and fora sufficient time to form an oxidized surface layer. This oxidized layeris highly resistive.

Plasma and plasma generators are well known. In general, a material isplaced in a vacuum chamber and held at a specific pressure in thepresence of the desired gas, and an electric field is applied. Theplasma reactions are controlled by controlling the gas mixtures, gaspressures, voltage, power density, temperature and time.

For plasma oxidation of the anode, at least one oxygen-containing gasmust be present. Exemplary oxygen-containing gases include O₂, COF₂, CO,O₃, NO, N₂O, and mixtures thereof. An inert may also be used. The inertgas may include any one or more of a noble gas, N₂, and mixturesthereof. The ratio of oxygen-containing gas to inert gas can be in therange of 10:0 to 1:10. In some embodiments, the oxygen-containing gas ismolecular oxygen and the inert gas is argon.

The gas pressure is maintained in the range of 1 to 1000 mTorr. In someembodiments, the gas pressure is 1 to 50 mTorr.

The voltage is in a range of approximately 5 to 1000 V, depending onwhether the plasma used is a capacitive-coupled type or a downstreamtype. The power densities are given in power per unit area of substrate.The power density is in a range of approximately 0.20 to 20 W/cm². Insome embodiments, the power density is in the range of 5 to 10 W/cm².

The temperature is in the range of 20-100° C. In some embodiments, thetemperature is in the range of 50-80° C.

The time of plasma oxidation is dependent upon the power density. Forlower power density plasmas, in the range of 0.20 to 1.0 W/cm², thetreating time is at least 10 minutes. For plasmas having a power densityin the range of 5-10 W/cm², times of 1-5 minutes can be used. Forplasmas having a power density of greater than 10 W/cm², even shortertimes can be used.

The anode oxidation will be more pronounced at the edges and at anyspikes due to the field concentration in the discharge, and thus provideincreased oxidation where it is required.

4. Organic Electronic Device

The term “organic electronic device” or sometimes just “electronicdevice” is intended to mean a device including one or more organicsemiconductor layers or materials. An organic electronic deviceincludes, but is not limited to: (1) a device that converts electricalenergy into radiation (e.g., a light-emitting diode, light emittingdiode display, diode laser, or lighting panel), (2) a device thatdetects a signal using an electronic process (e.g., a photodetector, aphotoconductive cell, a photoresistor, a photoswitch, a phototransistor,a phototube, an infrared (“IR”) detector, or a biosensors), (3) a devicethat converts radiation into electrical energy (e.g., a photovoltaicdevice or solar cell), (4) a device that includes one or more electroniccomponents that include one or more organic semiconductor layers (e.g.,a transistor or diode), or any combination of devices in items (1)through (4).

In some embodiments, the organic electronic device comprises:

-   -   a substrate,    -   an anode comprising a conducting inorganic material having an        oxidized surface layer which is non-conductive and        hole-transporting    -   at least one organic active layer, and    -   a cathode.

The substrate is a base material that can be either rigid or flexibleand may be include one or more layers of one or more materials, whichcan include, but are not limited to, glass, polymer, metal or ceramicmaterials or combinations thereof. In some embodiments, the substrate isglass.

In some embodiments, the substrate is a TFT substrate. TFT substratesare well known in the electronic art. The base support may be aconventional support as used in organic electronic device arts. The basesupport can be flexible or rigid, organic or inorganic. In someembodiments, the base support is transparent. In some embodiments, thebase support is glass or a flexible organic film. The TFT array may belocated over or within the support, as is known. The support can have athickness in the range of about 12 to 2500 microns.

The term “thin-film transistor” or “TFT” is intended to mean afield-effect transistor in which at least a channel region of thefield-effect transistor is not principally a portion of a base materialof a substrate. In one embodiment, the channel region of a TFT includesa-Si, polycrystalline silicon, or a combination thereof. The term“field-effect transistor” is intended to mean a transistor, whosecurrent carrying characteristics are affected by a voltage on a gateelectrode. A field-effect transistor includes a junction field-effecttransistor (JFET) or a metal-insulator-semiconductor field-effecttransistor (MISFET), including a metal-oxide-semiconductor field-effecttransistor (MOSFETs), a metal-nitride-oxide-semiconductor (MNOS)field-effect transistor, or the like. A field-effect transistor can ben-channel (n-type carriers flowing within the channel region) orp-channel (p-type carriers flowing within the channel region). Afield-effect transistor may be an enhancement-mode transistor (channelregion having a different conductivity type compared to the transistor'sS/D regions) or depletion-mode transistor (the transistor's channel andS/D regions have the same conductivity type).

The TFT substrate also includes a surface insulating layer. Althoughthis layer can be an organic planarization layer, any exposed organicmaterial will be removed with the plasma treatment. It is preferred tohave an inorganic passivation layer as the insulating layer. Anyinorganic dielectric material can be used. In some embodiments, theinorganic material is a metal oxide or nitride. In some embodiments, theinorganic material is selected from the group consisting of siliconoxides, silicon nitrides, or combinations thereof. In some embodiments,the inorganic passivation layer has a thickness of 50 to 500 nm; in someembodiments, 300-400 nm.

The organic layer or layers include one or more of a buffer layer, ahole transport layer, a photoactive layer, an electron transport layer,and an electron injection layer. The layers are arranged in the orderlisted.

The term “organic buffer layer” or “organic buffer material” is intendedto mean electrically conductive or semiconductive organic materials andmay have one or more functions in an organic electronic device,including but not limited to, planarization of the underlying layer,charge transport and/or charge injection properties, scavenging ofimpurities such as oxygen or metal ions, and other aspects to facilitateor to improve the performance of the organic electronic device. Organicbuffer materials may be polymers, oligomers, or small molecules, and maybe in the form of solutions, dispersions, suspensions, emulsions,colloidal mixtures, or other compositions.

The organic buffer layer can be formed with polymeric materials, such aspolyaniline (PANI) or polyethylenedioxythiophene (PEDOT), which areoften doped with protonic acids. The protonic acids can be, for example,poly(styrenesulfonic acid), poly(2-acrylamido-2-methyl-1-propanesulfonicacid), and the like. The organic buffer layer can comprise chargetransfer compounds, and the like, such as copper phthalocyanine and thetetrathiafulvalene-tetracyanoquinodimethane system (TTF-TCNQ). In oneembodiment, the organic buffer layer is made from a dispersion of aconducting polymer and a colloid-forming polymeric acid. Such materialshave been described in, for example, published U.S. patent applications2004-0102577, 2004-0127637, and 2005/205860. The organic buffer layertypically has a thickness in a range of approximately 20-200 nm.

Examples of hole transport materials have been summarized for example,in Kirk-Othmer Encyclopedia of Chemical Technology, Fourth Edition, Vol.18, p. 837-860, 1996, by Y. Wang. Both hole transporting molecules andpolymers can be used. Commonly used hole transporting molecules include,but are not limited to: 4,4′,4″-tris(N,N-diphenyl-amino)-triphenylamine(TDATA); 4,4′,4″-tris(N-3-methylphenyl-N-phenyl-amino)-triphenylamine(MTDATA);N,N′-diphenyl-N,N′-bis(3-methylphenyl)-[1,1′-biphenyl]-4,4′-diamine(TPD); 1,1-bis[(di-4-tolylamino) phenyl]cyclohexane (TAPC);N,N′-bis(4-methylphenyl)-N,N′-bis(4-ethylphenyl)-[1,1′-(3,3′-dimethyl)biphenyl]-4,4′-diamine(ETPD); tetrakis-(3-methylphenyl)-N,N,N′,N′-2,5-phenylenediamine (PDA);α-phenyl-4-N,N-diphenylaminostyrene (TPS); p-(diethylamino)benzaldehydediphenylhydrazone (DEH); triphenylamine (TPA);bis[4-(N,N-diethylamino)-2-methylphenyl](4-methylphenyl)methane (MPMP);1-phenyl-3-[p-(diethylamino)styryl]-5-[p-(diethylamino)phenyl]pyrazoline(PPR or DEASP); 1,2-trans-bis(9H-carbazol-9-yl)cyclobutane (DCZB);N,N,N′,N′-tetrakis(4-methylphenyl)-(1,1′-biphenyl)-4,4′-diamine (TTB);N,N′-bis(naphthalen-1-yl)-N,N′-bis-(phenyl)benzidine (α-NPB); andporphyrinic compounds, such as copper phthalocyanine. Commonly used holetransporting polymers include, but are not limited to,polyvinylcarbazole, (phenylmethyl)polysilane, poly(dioxythiophenes),polyanilines, and polypyrroles. It is also possible to obtain holetransporting polymers by doping hole transporting molecules such asthose mentioned above into polymers such as polystyrene andpolycarbonate. The hole transport layer typically has a thickness in arange of approximately 40-100 nm. Although light-emitting materials mayalso have some charge transport properties, the term “hole transportlayer” is not intended to include a layer whose primary function islight emission.

“Photoactive” refers to a material that emits light when activated by anapplied voltage (such as in a light emitting diode or chemical cell) orresponds to radiant energy and generates a signal with or without anapplied bias voltage (such as in a photodetector). Any organicelectroluminescent (“EL”) material can be used in the photoactive layer,and such materials are well known in the art. The materials include, butare not limited to, small molecule organic fluorescent compounds,fluorescent and phosphorescent metal complexes, conjugated polymers, andmixtures thereof. The photoactive material can be present alone, or inadmixture with one or more host materials. Examples of fluorescentcompounds include, but are not limited to, naphthalene, anthracene,chrysene, pyrene, tetracene, xanthene, perylene, coumarin, rhodamine,quinacridone, rubrene, derivatives thereof, and mixtures thereof.Examples of metal complexes include, but are not limited to, metalchelated oxinoid compounds, such as tris(8-hydroxyquinolato)aluminum(Alq3); cyclometalated iridium and platinum electroluminescentcompounds, such as complexes of iridium with phenylpyridine,phenylquinoline, or phenylpyrimidine ligands as disclosed in Petrov etal., U.S. Pat. No. 6,670,645 and Published PCT Applications WO 03/063555and WO 2004/016710, and organometallic complexes described in, forexample, Published PCT Applications WO 03/008424, WO 03/091688, and WO03/040257, and mixtures thereof. Examples of conjugated polymersinclude, but are not limited to poly(phenylenevinylenes), polyfluorenes,poly(spirobifluorenes), polythiophenes, poly(p-phenylenes), copolymersthereof, and mixtures thereof. The photoactive layer typically has athickness in a range of approximately 50-500 nm.

“Electron Transport” means when referring to a layer, material, memberor structure, such a layer, material, member or structure that promotesor facilitates migration of negative charges through such a layer,material, member or structure into another layer, material, member orstructure. Examples of electron transport materials which can be used inthe optional electron transport layer 140, include metal chelatedoxinoid compounds, such as tris(8-hydroxyquinolato)aluminum (AIQ),bis(2-methyl-8-quinolinolato)(p-phenylphenolato) aluminum (BAIq),tetrakis-(8-hydroxyquinolato)hafnium (HfQ) andtetrakis-(8-hydroxyquinolato)zirconium (ZrQ); and azole compounds suchas 2-(4-biphenylyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole (PBD),3-(4-biphenylyl)-4-phenyl-5-(4-t-butylphenyl)-1,2,4-triazole (TAZ), and1,3,5-tri(phenyl-2-benzimidazole)benzene (TPBI); quinoxaline derivativessuch as 2,3-bis(4-fluorophenyl)quinoxaline; phenanthrolines such as4,7-diphenyl-1,10-phenanthroline (DPA) and2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (DDPA); and mixturesthereof. The electron-transport layer typically has a thickness in arange of approximately 30-500 nm. Although light-emitting materials mayalso have some charge transport properties, the term “electron transportlayer” is not intended to include a layer whose primary function islight emission.

As used herein, the term “electron injection” when referring to a layer,material, member, or structure, is intended to mean such layer,material, member, or structure facilitates injection and migration ofnegative charges through the thickness of such layer, material, member,or structure with relative efficiency and small loss of charge. Theoptional electron-transport layer may be inorganic and comprise BaO,LiF, or Li₂O. The electron injection layer typically has a thickness ina range of approximately 20-100 Å.

The cathode can be selected from Group 1 metals (e.g., Li, Cs), theGroup 2 (alkaline earth) metals, the rare earth metals including thelanthanides and the actinides. The cathode a thickness in a range ofapproximately 300-1000 nm.

An encapsulating layer can be formed over the array and the peripheraland remote circuitry to form a substantially complete electrical device.

A process for forming an organic electronic device, comprises:

-   -   providing a TFT substrate having an inorganic surface layer;    -   forming a patterned anode on the TFT surface;    -   treating the anode with an oxygen plasma with a sufficient power        density and for a sufficient time to form a non-conductive,        hole-transport surface layer on the anode;    -   forming at least one organic active layer by a liquid deposition        technique;    -   applying a cathode.

In liquid deposition, an organic active material is formed into a layerfrom a liquid composition. The term “liquid composition” is intended tomean a liquid medium in which a material is dissolved to form asolution, a liquid medium in which a material is dispersed to form adispersion, or a liquid medium in which a material is suspended to forma suspension or an emulsion. The term “liquid medium” is intended tomean a liquid material, including a pure liquid, a combination ofliquids, a solution, a dispersion, a suspension, and an emulsion. Liquidmedium is used regardless whether one or more solvents are present.

Any known liquid deposition technique can be used, including continuousand discontinuous techniques. Continuous deposition techniques, includebut are not limited to, spin coating, gravure coating, curtain coating,dip coating, slot-die coating, spray coating, and continuous nozzlecoating. Discontinuous deposition techniques include, but are notlimited to, ink jet printing, gravure printing, and screen printing.

In some embodiments, the buffer layer, the hole transport layer and thephotoactive layer are formed by liquid deposition techniques. Theelectron transport layer, the electron injection layer and the cathodeare formed by vapor deposition techniques.

Detailed Description of FIG. 1

One embodiment of an organic electronic device structure is shown inFIG. 1. The device 100 has a first electrical contact layer, an anodelayer 110 and a second electrical contact layer, a cathode layer 160,and a photoactive layer 140 between them. A portion of the anode layer110 is oxidized to form an oxidized layer 105. Additional layers mayoptionally be present. Adjacent to the oxidized layer 105 may be abuffer layer 120. Adjacent to the buffer layer 120 may be a holetransport layer 130, comprising hole transport material. Adjacent to thecathode layer 160 may be an electron transport layer 150, comprising anelectron transport material. As an option, devices may use one or moreadditional hole injection or hole transport layers (not shown) next tothe oxidized layer 105 and/or one or more additional electron injectionor electron transport layers (not shown) next to the cathode 160. Layers120 through 150 are individually and collectively referred to as theactive layers.

EXAMPLES

The concepts described herein will be further described in the followingexamples, which do not limit the scope of the invention described in theclaims.

Example 1

Example 1 demonstrates the formation of an anode having an oxidizedsurface layer.

Using the March PX500 system, 300 W of power was applied to a surface ofITO which was 10 inch×18 inch in dimension, giving 0.25 W/cm² for 10minutes. The gas pressure used was ˜200 mTorr with gases of argon andoxygen. The ratio of Ar to O₂ used was 7.5:2.5. The role of Argon is toenhance the Penning dissociation of oxygen.

Note that not all of the activities described above in the generaldescription or the examples are required, that a portion of a specificactivity may not be required, and that one or more further activitiesmay be performed in addition to those described. Still further, theorder in which activities are listed are not necessarily the order inwhich they are performed.

In the foregoing specification, the concepts have been described withreference to specific embodiments. However, one of ordinary skill in theart appreciates that various modifications and changes can be madewithout departing from the scope of the invention as set forth in theclaims below. Accordingly, the specification and figures are to beregarded in an illustrative rather than a restrictive sense, and allsuch modifications are intended to be included within the scope ofinvention.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any feature(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature of any or all the claims.

It is to be appreciated that certain features are, for clarity,described herein in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures that are, for brevity, described in the context of a singleembodiment, may also be provided separately or in any subcombination.Further, reference to values stated in ranges include each and everyvalue within that range.

What is claimed is:
 1. A process for forming an organic electronicdevice, comprising: providing a TFT substrate having an inorganicsurface layer; forming a patterned anode on the TFT surface; treatingthe anode with an oxygen plasma with a sufficient power density and fora sufficient time to form a non-conductive, hole-transport surface layeron the anode; forming at least one organic active layer on thenon-conductive, hole-transport surface layer by a liquid depositiontechnique; applying a cathode to the at least one organic active layer.2. The process of claim 1, wherein the plasma consists essentially ofargon and oxygen with a volume ratio in the range of 9:1 to 0:10.
 3. Theprocess of claim 1, wherein the power density is in the range of 0.25 to1.0 W/cm², and the treating time is at least 10 minutes.
 4. The processof claim 1, wherein the power density is greater than 10 W/cm².